Designs that have a whiff of complex impenetrability tends to suggest big, complicated ideas. Academic writing tends to work the same way, I understand.
It's hard to predict what will happen as reading on screen becomes more of a universal norm, and when the formats dictated by social media - Twitter's 140-character limit, for instance - start to influence what we're used to.
I believe sans serif typefaces - today upheld as models of neutrality and legibility - were called "Grotesques" in the 19th century because people thought they were hideous. But now we're used to them.
Compared with now when almost everyone knows what graphic design is and has some sort of access to the tools to make it, back then, it was really esoteric, you had to quantify it as being 'like commercial art', as one still does in certain circles. It was a strange thing to want to do for a living.
In the US you have New York, San Francisco, Los Angeles, Boston, Miami and dozens of other cities; a few of them have a really strong visual character. But even with those there is just too much space between them and too many people.
I actually think it almost works the other way sometimes: making a college textbook, say, look really "user friendly" tends to also make it look less "serious," even if nothing changes other than the design treatment.